围岩土层条件对地下框架结构地震破坏反应的影响

    Influence of Surrounding Soil Condition on Earthquake Damage Response of Underground Frame Structures

    • 摘要: 以大开站及高速长田站在阪神地震中出现的不同地震破坏现象为例,基于能够合理模拟实际地铁车站地震破坏数值有限元分析方法,探讨不同围岩土层条件对地下框架结构地震破坏反应的影响.研究结果表明:不同的围岩土层条件,导致大开站与高速长田站场地在相同地震作用下所产生的相对变形与加速度分布均不相同,主要表现为大开站车站结构顶底板所在位置的土层水平相对位移显著大于高速长田站,进而导致大开站立柱顶底端水平相对位移显著大于高速长田站;当处于较高的轴压比条件时,大开站立柱由于受到过量的水平相对变形,致使其侧向变形能力严重不足从而发生脆性破坏,导致车站结构整体塌毁.高速长田站则由于立柱的地震反应一直处于其自身承载能力范围内而未出现严重震害现象.

       

      Abstract: During the Kobe earthquake in Japan, different degrees of earthquake damage occurred on the Daikai subway station and Kusokunagata subway station. These two stations have almost the same structure construction but different surrounding soil conditions. Based on nonlinear finite element analyses, influences of surrounding soil condition on earthquake damage response of underground frame structures were investigated. Numerical results indicate that different surrounding soil conditions lead to different seismic responses of the Daikai station with those of the Kusokunagata station. The horizontal relative deformation between the soil layers which are located at the same depth with the structural lower end and upper end of the Daikai station is significantly greater than that of the Kusokunagata station. Therefore, the horizontal relative deformation of structural lower end and upper end comparison of the two stations is also the same. The excessive lateral deformation and the high axial compression ratio jointly made the brittle failure appear in the columns of the Daikai station, which leads to the overall disrepair of the structural frame. Whereas, little lateral deformation appeared in the column of the Kusokunagata station because its response to the earthquake did not exceed its loading limit and the entire station survived during the earthquake.

       

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